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 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package com.sun.jmx.snmp;

import com.sun.jmx.snmp.SnmpSecurityParameters;
// java imports
//
import java.util.Vector;
import java.net.InetAddress;

import com.sun.jmx.snmp.SnmpStatusException;

/**
 * A partially decoded representation of an SNMP packet. It contains
 * the information contained in any SNMP message (SNMPv1, SNMPv2 or
 * SNMPv3).
 * <p><b>This API is a Sun Microsystems internal API  and is subject
 * to change without notice.</b></p>
 * @since 1.5
 */
public abstract class SnmpMsg implements SnmpDefinitions {
    /**
     * The protocol version.
     * <P><CODE>decodeMessage</CODE> and <CODE>encodeMessage</CODE> do not
     * perform any check on this value.
     * <BR><CODE>decodeSnmpPdu</CODE> and <CODE>encodeSnmpPdu</CODE> only
     * accept  the values 0 (for SNMPv1), 1 (for SNMPv2) and 3 (for SNMPv3).
     */
    public int version = 0;

    /**
     * Encoding of the PDU.
     * <P>This is usually the BER encoding of the PDU's syntax
     * defined in RFC1157 and RFC1902. However, this can be authenticated
     * or encrypted data (but you need to implemented your own
     * <CODE>SnmpPduFactory</CODE> class).
     */
    public byte[] data = null;

    /**
     * Number of useful bytes in the <CODE>data</CODE> field.
     */
    public int dataLength = 0;

    /**
     * Source or destination address.
     * <BR>For an incoming message it's the source.
     * For an outgoing message it's the destination.
     */
    public InetAddress address = null;

    /**
     * Source or destination port.
     * <BR>For an incoming message it's the source.
     * For an outgoing message it's the destination.
     */
    public int port = 0;
    /**
     * Security parameters. Contain informations according to Security Model (Usm, community string based, ...).
     */
    public SnmpSecurityParameters securityParameters = null;

    /**
     * Returns the encoded SNMP version present in the passed byte array.
     * @param data The unmarshalled SNMP message.
     * @return The SNMP version (0, 1 or 3).
     */
    public static int getProtocolVersion(byte[] data) throws SnmpStatusException {
        int version = 0;
        BerDecoder bdec = null;
        try {
            bdec = new BerDecoder(data);
            bdec.openSequence();
            version = bdec.fetchInteger();
        } catch (BerException x) {
            throw new SnmpStatusException("Invalid encoding");
        }
        try {
            bdec.closeSequence();
        } catch (BerException x) {
        }
        return version;
    }

    /**
     * Returns the associated request ID.
     * @param data The flat message.
     * @return The request ID.
     */
    public abstract int getRequestId(byte[] data) throws SnmpStatusException;

    /**
     * Encodes this message and puts the result in the specified byte array.
     * For internal use only.
     *
     * @param outputBytes An array to receive the resulting encoding.
     *
     * @exception ArrayIndexOutOfBoundsException If the result does not fit
     *                                           into the specified array.
     */
    public abstract int encodeMessage(byte[] outputBytes) throws SnmpTooBigException;

    /**
    * Decodes the specified bytes and initializes this message.
    * For internal use only.
    *
    * @param inputBytes The bytes to be decoded.
    *
    * @exception SnmpStatusException If the specified bytes are not a valid encoding.
    */
    public abstract void decodeMessage(byte[] inputBytes, int byteCount) throws SnmpStatusException;

    /**
    * Initializes this message with the specified <CODE>pdu</CODE>.
    * <P>
    * This method initializes the data field with an array of
    * <CODE>maxDataLength</CODE> bytes. It encodes the <CODE>pdu</CODE>.
    * The resulting encoding is stored in the data field
    * and the length of the encoding is stored in <CODE>dataLength</CODE>.
    * <p>
    * If the encoding length exceeds <CODE>maxDataLength</CODE>,
    * the method throws an exception.
    *
    * @param pdu The PDU to be encoded.
    * @param maxDataLength The maximum length permitted for the data field.
    *
    * @exception SnmpStatusException If the specified <CODE>pdu</CODE> is not valid.
    * @exception SnmpTooBigException If the resulting encoding does not fit
    * into <CODE>maxDataLength</CODE> bytes.
    * @exception ArrayIndexOutOfBoundsException If the encoding exceeds <CODE>maxDataLength</CODE>.
    */
    public abstract void encodeSnmpPdu(SnmpPdu pdu, int maxDataLength) throws SnmpStatusException, SnmpTooBigException;

    /**
     * Gets the PDU encoded in this message.
     * <P>
     * This method decodes the data field and returns the resulting PDU.
     *
     * @return The resulting PDU.
     * @exception SnmpStatusException If the encoding is not valid.
     */
    public abstract SnmpPdu decodeSnmpPdu() throws SnmpStatusException;

    /**
     * Dumps the content of a byte buffer using hexadecimal form.
     *
     * @param b The buffer to dump.
     * @param offset The position of the first byte to be dumped.
     * @param len The number of bytes to be dumped starting from offset.
     *
     * @return The string containing the dump.
     */
    public static String dumpHexBuffer(byte[] b, int offset, int len) {
        StringBuffer buf = new StringBuffer(len << 1);
        int k = 1;
        int flen = offset + len;

        for (int i = offset; i < flen; i++) {
            int j = b[i] & 0xFF;
            buf.append(Character.forDigit((j >>> 4), 16));
            buf.append(Character.forDigit((j & 0x0F), 16));
            k++;
            if (k % 16 == 0) {
                buf.append('\n');
                k = 1;
            } else
                buf.append(' ');
        }
        return buf.toString();
    }

    /**
     * Dumps this message in a string.
     *
     * @return The string containing the dump.
     */
    public String printMessage() {
        StringBuffer sb = new StringBuffer();
        sb.append("Version: ");
        sb.append(version);
        sb.append("\n");
        if (data == null) {
            sb.append("Data: null");
        } else {
            sb.append("Data: {\n");
            sb.append(dumpHexBuffer(data, 0, dataLength));
            sb.append("\n}\n");
        }

        return sb.toString();
    }

    /**
     * For SNMP Runtime private use only.
     */
    public void encodeVarBindList(BerEncoder benc, SnmpVarBind[] varBindList) throws SnmpStatusException, SnmpTooBigException {
        //
        // Remember: the encoder does backward encoding
        //
        int encodedVarBindCount = 0;
        try {
            benc.openSequence();
            if (varBindList != null) {
                for (int i = varBindList.length - 1; i >= 0; i--) {
                    SnmpVarBind bind = varBindList[i];
                    if (bind != null) {
                        benc.openSequence();
                        encodeVarBindValue(benc, bind.value);
                        benc.putOid(bind.oid.longValue());
                        benc.closeSequence();
                        encodedVarBindCount++;
                    }
                }
            }
            benc.closeSequence();
        } catch (ArrayIndexOutOfBoundsException x) {
            throw new SnmpTooBigException(encodedVarBindCount);
        }
    }

    /**
     * For SNMP Runtime private use only.
     */
    void encodeVarBindValue(BerEncoder benc, SnmpValue v) throws SnmpStatusException {
        if (v == null) {
            benc.putNull();
        } else if (v instanceof SnmpIpAddress) {
            benc.putOctetString(((SnmpIpAddress) v).byteValue(), SnmpValue.IpAddressTag);
        } else if (v instanceof SnmpCounter) {
            benc.putInteger(((SnmpCounter) v).longValue(), SnmpValue.CounterTag);
        } else if (v instanceof SnmpGauge) {
            benc.putInteger(((SnmpGauge) v).longValue(), SnmpValue.GaugeTag);
        } else if (v instanceof SnmpTimeticks) {
            benc.putInteger(((SnmpTimeticks) v).longValue(), SnmpValue.TimeticksTag);
        } else if (v instanceof SnmpOpaque) {
            benc.putOctetString(((SnmpOpaque) v).byteValue(), SnmpValue.OpaqueTag);
        } else if (v instanceof SnmpInt) {
            benc.putInteger(((SnmpInt) v).intValue());
        } else if (v instanceof SnmpString) {
            benc.putOctetString(((SnmpString) v).byteValue());
        } else if (v instanceof SnmpOid) {
            benc.putOid(((SnmpOid) v).longValue());
        } else if (v instanceof SnmpCounter64) {
            if (version == snmpVersionOne) {
                throw new SnmpStatusException("Invalid value for SNMP v1 : " + v);
            }
            benc.putInteger(((SnmpCounter64) v).longValue(), SnmpValue.Counter64Tag);
        } else if (v instanceof SnmpNull) {
            int tag = ((SnmpNull) v).getTag();
            if ((version == snmpVersionOne) && (tag != SnmpValue.NullTag)) {
                throw new SnmpStatusException("Invalid value for SNMP v1 : " + v);
            }
            if ((version == snmpVersionTwo) && (tag != SnmpValue.NullTag) && (tag != SnmpVarBind.errNoSuchObjectTag) && (tag != SnmpVarBind.errNoSuchInstanceTag) && (tag != SnmpVarBind.errEndOfMibViewTag)) {
                throw new SnmpStatusException("Invalid value " + v);
            }
            benc.putNull(tag);
        } else {
            throw new SnmpStatusException("Invalid value " + v);
        }

    }

    /**
     * For SNMP Runtime private use only.
     */
    public SnmpVarBind[] decodeVarBindList(BerDecoder bdec) throws BerException {
        bdec.openSequence();
        Vector<SnmpVarBind> tmp = new Vector<SnmpVarBind>();
        while (bdec.cannotCloseSequence()) {
            SnmpVarBind bind = new SnmpVarBind();
            bdec.openSequence();
            bind.oid = new SnmpOid(bdec.fetchOid());
            bind.setSnmpValue(decodeVarBindValue(bdec));
            bdec.closeSequence();
            tmp.addElement(bind);
        }
        bdec.closeSequence();
        SnmpVarBind[] varBindList = new SnmpVarBind[tmp.size()];
        tmp.copyInto(varBindList);
        return varBindList;
    }

    /**
     * For SNMP Runtime private use only.
     */
    SnmpValue decodeVarBindValue(BerDecoder bdec) throws BerException {
        SnmpValue result = null;
        int tag = bdec.getTag();

        // bugId 4641696 : RuntimeExceptions must be transformed in
        //                 BerException.
        switch (tag) {

            //
            // Simple syntax
            //
            case BerDecoder.IntegerTag:
                try {
                    result = new SnmpInt(bdec.fetchInteger());
                } catch (RuntimeException r) {
                    throw new BerException();
                    // BerException("Can't build SnmpInt from decoded value.");
                }
                break;
            case BerDecoder.OctetStringTag:
                try {
                    result = new SnmpString(bdec.fetchOctetString());
                } catch (RuntimeException r) {
                    throw new BerException();
                    // BerException("Can't build SnmpString from decoded value.");
                }
                break;
            case BerDecoder.OidTag:
                try {
                    result = new SnmpOid(bdec.fetchOid());
                } catch (RuntimeException r) {
                    throw new BerException();
                    // BerException("Can't build SnmpOid from decoded value.");
                }
                break;
            case BerDecoder.NullTag:
                bdec.fetchNull();
                try {
                    result = new SnmpNull();
                } catch (RuntimeException r) {
                    throw new BerException();
                    // BerException("Can't build SnmpNull from decoded value.");
                }
                break;

            //
            // Application syntax
            //
            case SnmpValue.IpAddressTag:
                try {
                    result = new SnmpIpAddress(bdec.fetchOctetString(tag));
                } catch (RuntimeException r) {
                    throw new BerException();
                    // BerException("Can't build SnmpIpAddress from decoded value.");
                }
                break;
            case SnmpValue.CounterTag:
                try {
                    result = new SnmpCounter(bdec.fetchIntegerAsLong(tag));
                } catch (RuntimeException r) {
                    throw new BerException();
                    // BerException("Can't build SnmpCounter from decoded value.");
                }
                break;
            case SnmpValue.GaugeTag:
                try {
                    result = new SnmpGauge(bdec.fetchIntegerAsLong(tag));
                } catch (RuntimeException r) {
                    throw new BerException();
                    // BerException("Can't build SnmpGauge from decoded value.");
                }
                break;
            case SnmpValue.TimeticksTag:
                try {
                    result = new SnmpTimeticks(bdec.fetchIntegerAsLong(tag));
                } catch (RuntimeException r) {
                    throw new BerException();
                    // BerException("Can't build SnmpTimeticks from decoded value.");
                }
                break;
            case SnmpValue.OpaqueTag:
                try {
                    result = new SnmpOpaque(bdec.fetchOctetString(tag));
                } catch (RuntimeException r) {
                    throw new BerException();
                    // BerException("Can't build SnmpOpaque from decoded value.");
                }
                break;

            //
            // V2 syntaxes
            //
            case SnmpValue.Counter64Tag:
                if (version == snmpVersionOne) {
                    throw new BerException(BerException.BAD_VERSION);
                }
                try {
                    result = new SnmpCounter64(bdec.fetchIntegerAsLong(tag));
                } catch (RuntimeException r) {
                    throw new BerException();
                    // BerException("Can't build SnmpCounter64 from decoded value.");
                }
                break;

            case SnmpVarBind.errNoSuchObjectTag:
                if (version == snmpVersionOne) {
                    throw new BerException(BerException.BAD_VERSION);
                }
                bdec.fetchNull(tag);
                result = SnmpVarBind.noSuchObject;
                break;

            case SnmpVarBind.errNoSuchInstanceTag:
                if (version == snmpVersionOne) {
                    throw new BerException(BerException.BAD_VERSION);
                }
                bdec.fetchNull(tag);
                result = SnmpVarBind.noSuchInstance;
                break;

            case SnmpVarBind.errEndOfMibViewTag:
                if (version == snmpVersionOne) {
                    throw new BerException(BerException.BAD_VERSION);
                }
                bdec.fetchNull(tag);
                result = SnmpVarBind.endOfMibView;
                break;

            default:
                throw new BerException();

        }

        return result;
    }

}
